Peak Swede Midge activity in canola can run into mid-June in Ontario.
OMAFRA specialists warn planting canola fields in areas of known infection is among the most significant risk factors.
Other risk factors include late planted fields, because they will be in the younger vulnerable stages of the crop when adult Swede midge activity is peaking.
Canola fields under stress from other factors are also at risk.
The ministry says Swede midge requires intensive monitoring and management to protect the crop from injury.
Growers are advised to start trapping once seedlings have one true leaf.
When the number of adults trapped hits 20, it's time for the first insecticide application.
Even at that, OMAFRA points out currently registered products do not provide 100 per cent control of Swede Midge.
More details on rates and label precautions for chemical control are in the OMAFRA Field Crop Protection Guide.
